Bernie Masters is a geologist/zoologist who spent 8 years as a member of the Western Australian Parliament. Married to Carolina since 1976 and living in south west WA, Bernie is involved in many community groups. This blog offers insights into politics, the environment and other issues that annoy or interest him. For something completely different, visit www.fiatechnology.com.au for information about vegetated floating islands - the natural way to improve water quality.

Cancer
Council Australia and the Prostate Cancer Foundation of Australia yesterday
released new draft guidelines to help GPs counsel men who ask about
prostate cancer tests. They advise GPs to explain the pros and cons of testing
and, if the man wants to proceed, to give him a prostate specific antigen (PSA)
blood test every two years between the ages of 50 to 69.

Over the past few decades
public health messages have drummed into us that early detection and treatment
of diseases are key to good outcomes. Add to this the celebrity testimonials
for prostate tests and non-celebrities who tell us their PSA test “saved their
life” and it’s easy to see why men think the tests are beneficial.

While some prostate cancers
are harmful and require treatment, many are not. So the prevailing wisdom –
that early detection and treatment is best – doesn’t necessarily apply. At
least 70% of men over 70 have prostate cancer detected
in autopsies, and only 3% of men die because of prostate cancer.

I’m a 60-year-old male
oncologist who has practised full-time for 36 years. Having “skin in the game”
I’ve followed the testing debate closely since PSA was first used for screening
in the early 1990s. Based on the evidence, if I was asymptomatic, I would not
choose to have PSA test. Here’s why.

1. PSA is a poor testing tool

Prostate
specific antigen (PSA) is an enzyme secreted in large amounts by normal as well
as cancerous prostate cells. Only small amounts of PSA leak into circulation
from a normal prostate, but this increases with any prostatic disease, benign
or malignant.

An elevated PSA very often
does not indicate cancer. Just one in four men with a positive PSA test
will have prostate cancer.

PSA tests also miss many
cancers. A 2003 study found that 21% of men who had a
“normal” PSA of 2.6 to 3.9 at the end of a seven-year study did, in fact, have
prostate cancer. Of the men with a PSA of 2.5 or less, 15% had cancer.

2. Prostate cancer isn’t like other
cancers

The
point of a cancer screening test is that it can reliably detect lesions that,
if removed, will reduce the chances of that patient later developing a
life-threatening cancer.

This is certainly true for
polyps and bowel cancer screening. It is also powerfully true for precancerous
lesions of the cervix and cervical cancer. It is somewhat true for mammography
and precancerous or early invasive breast lesions.

It is not at all true for
prostate cancer screening. In the majority of cases, prostate cancer behaves
more like an indolent condition and does not pose any threat to the patient’s
natural life span. This proportion of men dying of other causes continues to increase
in the PSA era.

The only study comparing radical surgery with no
treatment found equivalent outcomes. It concluded:

Among men with localized
prostate cancer detected during the early era of PSA testing, radical
prostatectomy did not significantly reduce all-cause or prostate-cancer
mortality, as compared with observation, through at least 12 years of
follow-up. Absolute differences were less than three percentage points.

Radical surgery “cures” six
in seven cases of prostate cancer. But this does not remove the uncertainty and
doubt for men with prostate cancer, as most of the six in seven who are “cured”
did not require treatment and most of the one in seven with dangerous cancers
requiring cure will not be helped by the treatment.

4. Detection and treatment comes
with side effects

One in six men will be diagnosed with
prostate cancer during his lifetime. Their lives will be profoundly changed by
this cancer diagnosis, whether or not they proceed with treatment.

I do not want the anxiety,
depression and relationship changes that follow diagnosis, radical surgery,
active surveillance or any regular monitoring. I do not want to be impotent,
which is very likely after radical treatment, or have urinary incontinence.

Even before treatment
commences, after an abnormal PSA result, men are referred for a prostate
biopsy: a surgical procedure that, even though it can indicate cancer, cannot
give reliable information about how that cancer will behave.

I do not want the 1-2% risk
of life-threatening infections caused by prostate biopsies.

Bottom line

I’m happy to take active
positive steps to improve my health where it is proven that the benefits of the
intervention outweigh the costs. But I’m not prepared to have my life ruled by
a regular blood test like PSA that has no advantage.